1. Field of Invention
The present invention relates to a device of double saw blades, which has two saw blades rotating oppositely along the same axis and respectively having a cutting element mounting on the periphery thereof, and more particularly to a device of double saw blades which is capable of reducing abrasion and collision between the two saw blades, so that the double saw blades have long service life and high efficiency.
2. Description of Related Arts
The devices of double saw blades which rotate oppositely along the same axis are applied widely due to the advantages such as fast cutting and stable working. However, the devices have some common drawbacks. When working, because of its fast rotation and pressure by the object being cut, abrasion and collision often happens between the two saw blades, especially at their peripheries. Accordingly, the saw blades may be damaged, even worse, there may be flying fragments to hurt people. Besides, a gap is ordinarily remained between the two saw blades for not blocking rotation of each other. Nonetheless, the gap brings noise, and the sawdust can entered the gap easily. As a result, abrasion between the two saw blades is increased, and the saw blades may even be deformed under pressure of the sawdust.
Additionally, the devices of double saw blades are ordinarily driven by shaft. The shaft mounts on the center of the devices of double saw blades via an adapter. Traditionally, the adapter is only used to fix and fasten the saw blades, and therefore does not need large size. For example, with regard to the saw blade having diameter of 125-165 mm, the diameter of the adapter is ordinarily 25 mm, which is much smaller than the diameter of the driving device. Accordingly, cutting depth is determined by the distance between the saw teeth and the driving device. Referring to FIG. 6, according to a conventional device of double saw blades, the diameter of the adapter is D, the diameter of the driving device is d, and the cutting depth is h.
To reduce abrasion and collision between the two saw blades, traditional methods comprise: increasing the distance between the two saw blades, or arranging a spacing member between the two saw blades.
If increasing the distance between the two saw blades, the cutting efficiency will be reduced, and the sawdust will enter into the gap between the two saw blades easily. Someone increases the distance between the two saw blades by respectively cutting the two opposite inner walls of the two saw blades, but the stress on the two saw blades is also increased, too, and therefore the saw blades are easier to be deformed.
The spacing member arranged between the two saw blades can prevent direct abrasion and collision between the two saw blades, but the spacing member still rubs with the two saw blades continuously and generates a great deal of heat. As a result, the heat and the abrasion causes that the saw blades using spacing member ordinarily have life of only few hours.